1. Field of the Invention
The present invention relates to an image display apparatus and an image recording apparatus and, more particularly, to a technique suitable for an apparatus for displaying display images on image display means on the basis of a plurality of input images with a parallax, so that an observer visually recognizes a plurality of observation images formed by the display images with his or her eyes, and recognizes them as a stereoscopic image.
2. Related Background Art
Conventionally, many image display apparatuses which independently present a plurality of images with a parallax to the two eyes of an observer so as to cause the observer to recognize a stereoscopic image have been proposed. Chihiro Masuda, "Three-dimensional Display" (Sangyo Tosho) discloses various types of stereoscopic image display apparatuses, as will be described below.
For the sake of easy understanding, images observed by the two eyes of an observer will be referred to as "observation images" hereinafter, images fetched from an object by input means will be referred to as "input images" hereinafter, and images displayed on image display means for the purpose of observation will be referred to as "display images" hereinafter.
FIG. 1 is an explanatory view of a three-dimensional display (stereoscopic image display apparatus) of an anaglyph method. In this method, a display image for the right eye and a display image for the left eye are respectively superimpose-displayed in two colors, e.g., red and blue, and observation images for the right and left eyes are separated using color filters, thus allowing an observer to recognize a stereoscopic image.
FIG. 2 is an explanatory view of a three-dimensional display of a polarizing glass method. In this method, a display image for the right eye and a display image for the left eye are respectively displayed on CRTs. Polarizing filters (polarizing plates) having orthogonal planes of oscillation and a half mirror are arranged in front of the CRTs. Observation images for the right and left eyes are separated by polarizing glasses, thus allowing an observer to recognize a stereoscopic image.
FIG. 3 is an explanatory view of a three-dimensional display of a time sharing shutter method. In this method, display images for the right and left eyes are alternately displayed on a CRT in a time sharing manner, and observation images for the right and left eyes are separated using time sharing shutter glasses which are opened/closed in a time sharing manner in synchronism with the display images, thus allowing an observer to recognize a stereoscopic image.
FIG. 4 is an explanatory view of an optical method. In this method, display images for the right and left eyes, which are separately displayed on a viewer using optical means such as prisms, mirror, lens, and the like, are superimpose-displayed as observation images in front of an observer, thus allowing the observer to recognize a stereoscopic image.
FIG. 5 is an explanatory view of a three-dimensional display of a lenticular method. In this method, a plurality of input images input by a lenticular lens are separately displayed via corresponding lenticular lens portions, thus allowing a plurality of observers to recognize a stereoscopic image.
FIGS. 6A and 6B are explanatory views of a three-dimensional display of large convex lens and large concave mirror methods. FIG. 6A shows the principle of the large convex lens method, and FIG. 6B shows the principle of the large concave mirror method. In this method, display images for the right and left eyes are formed on a large convex lens or a large concave mirror using projectors, and are displayed while determining the setting positions of the projectors and the spatial positions of the display images for the right and left eyes, so that light rays from the corresponding display images are incident on the right and left eyes, thus allowing an observer to recognize a stereoscopic image.
FIG. 7 is an explanatory view of a three-dimensional display of a parallax barrier method. In this method, a slit-shaped barrier (parallax barrier) is disposed in front of image display means to split a display image into right and left display images, and the right and left visual axes recognize these display images as observation images via the barrier, thus allowing an observer to recognize a stereoscopic image.
FIGS. 8A, 8B, and 8C are explanatory views of a three-dimensional display of an integral method. In this method, a large number of parallax images of an object are received (input) and recorded by an image taking device via a fly eye lens (FIG. 8A), and are transferred to a display device to be displayed as an image on the display device. The respective parallax images spatially form a real image at an identical position as that in the image taking operation. When an observer observes this real image from various directions, he or she can observe a parallax image corresponding to the observation direction, thus allowing stereoscopic viewing (FIGS. 8B and 8C).
On the other hand, as an input method of input images with a parallax, which are used in each of the above-mentioned image display apparatuses, a method of taking an image of an object from a plurality of directions using a plurality of cameras is normally used. When only two input images with a parallax for the right and left eyes are required like in the anaglyph method, polarizing glass method, time sharing shutter method, optical method, and the like, two image taking cameras Y.sub.R and Y.sub.L need only be used for an object X to be taken, as shown in FIG. 9, so as to obtain input images X.sub.R and X.sub.L.
However, the lenticular method, large convex lens/large concave mirror method, parallax barrier method, and the like require input images with a parallax from three or more view points in some cases. Thus, such methods require multi-lens camera input means, as shown in FIG. 25 (reference numerals in FIG. 25 will be described in detail later).
Note that the integral method inputs images via a special-purpose fly eye lens.
On the other hand, in recent years, input images actually taken by cameras are subjected to image processing attained by arithmetic operations of a computer so as to obtain parallax images for stereoscopic viewing, and such images are often used in stereoscopic viewing. In some cases, images of an object processed to appear to have been taken from quite different directions are generated and input on the basis of several input images, and such images are often used in the above-mentioned stereoscopic image display apparatus.
Furthermore, input images with a parallax, which are called CG (computer graphics) and are artificially synthesized by arithmetic operations using a computer, are often used in place of input images actually taken by cameras. When a CG method which performs image generation by accurately recognizing object configuration information in a three-dimensional space is used, since a plurality of input images with a. parallax can be formed on the basis of single three-dimensional information, such a method can be easily applied to the stereoscopic image display apparatus.
The above-mentioned stereoscopic image display utilizing a binocular parallax has no established display condition between the observation images for the right and left eyes, but is premised on the simple assumption that images for the right and left eyes are displayed under an identical condition. No image display apparatus which sets the display condition for images for the right and left eyes in consideration of effects to be given to an observer is available.
Similarly, as for the image input apparatus for inputting images to the image display apparatus for displaying a stereoscopic image, no apparatus which sets the display condition for images for the right and left eyes in consideration of effects to be given to an observer is available.